Publication

Abstract : This numerical study investigates steady separated flow past a grooved circular cylinder within the Reynolds number range (Formula presented.), comprising variations in groove depth ((Formula presented.)) and spacing ((Formula presented.)). The groove width ((Formula presented.)) is kept constant, while h/w varies across four levels ((Formula presented.)) and (Formula presented.) across five angles ((Formula presented.)). The results exhibit strong agreement with unbounded flow data, confirming blockage independence across the examined regime. Detailed analysis shows that (Formula presented.) has a stronger influence than (Formula presented.) on surface-pressure-dependent variables ((Formula presented.), (Formula presented.), (Formula presented.), (Formula presented.)) and wake-defining parameters ((Formula presented.), (Formula presented.), (Formula presented.), (Formula presented.)), underscoring the dominant role of (Formula presented.) in rectilinear groove aerodynamics. In this regard, a critical spacing of (Formula presented.) is observed, beyond which the sensitivity of the parameters toward the cylinder configuration decreases. Thus, significant flow control and drag reduction are attained for (Formula presented.) at the lowest spacing (Formula presented.), regardless of the groove’s (Formula presented.). Among these, the streamwise-oriented variables, (Formula presented.), (Formula presented.), (Formula presented.), (Formula presented.), and (Formula presented.), exhibit monotonic trend with respect to (Formula presented.) and are modeled using power-law relations. The models for (Formula presented.) and (Formula presented.) exhibit significant accuracy with (Formula presented.) across all (Formula presented.) values considered, while it is 0.89–0.98 for (Formula presented.), (Formula presented.), and (Formula presented.), depending on (Formula presented.). Transverse-oriented parameters ((Formula presented.)) vary non-monotonically. In addition, it is found that the streamwise locations of maximum wake width ((Formula presented.)) and minimum velocity ((Formula presented.)) are unaffected by the grooved cylinder configuration. © 2025 by the authors.